Rounding Errors
Discuss Rounding.
"I realised today that if your number has been rounded to two decimal places as 7.15, then you actually can't know if the nearest one-decimal-place number is 7.1 or 7.2."
"Our gradebook allows us to round to 0,1,2 or 3 decimals. Kid displays 79.4; could round to 80 because it's 79.49 which rounds to 79.5 which rounds to 80. Don't know unless you see multiple places."
"Kid would show 79.5 but earn a 79 because he really had 79.49. If we only display 1 dec, hard to understand. Took lots of guessing to figure that out!"
Which of these statements has merit?
Why? Why not?
I realised today that if your number has been rounded to two decimal places as 7.15, then you actually can't know if the nearest one-decimal-place number is 7.1 or 7.2.
— David Butler (@DavidKButlerUoA) August 31, 2020
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